Abstract

In 1981, psychologist James Flynn noticed that IQ scores had risen streadily over nearly a century a staggering difference
of 18 points over two generations. After a careful analysis, he concluded the cause to be culture. Society had become more intelligent—come to grips with bigger, more abstract ideas over time—and had made people smarter.
This observation, combined with solid evidence that IQ scores are also not fixed within an individual, neatly dispels the
idea of intelligence being an innate and fixed entity. While intelligence clearly has a biological component, it is best defined,
as a set of continually developed skills. WIREs Cogn Sci 2017, 8:e1366. doi: 10.1002/wcs.1366

Images

Gains in IQ tests in five nations over time. Note that specific scores for any given year should not be compared from one nation to another, as each nation's scores are normed only within their own group. The similarity of the changes over time, however, are fair to compare. From Flynn.